My 79 is shaking when I hit the brakes. All the Brakes seem fine and I can't find anything out of place i just don't know.

 

Sounds like you've got some warped rotors. Jack the truck and spin the wheel, if they're warped you have resistance at a certain point of rotation. Super commen to warp the rotors, especially if they have got hot quickly. Also the cheiper the rotor the more likely it is to warp.

 

Agreed